"Length?"
"Three centimeters."
Thom asked if he should add to the profile that the kidnapper had brown hair.
Rhyme said no. "We'll wait for some corroboration. Just write down that we know he wears a ski mask, navy blue. Fingernail scrapings, Mel?"
Cooper examined the trace but found nothing useful.
"The print you found. The one on the wall. Let's take a look at it. Could you show it to me, Amelia?"
Sachs hesitated then carried the Polaroid over to him.
"Your monster," Rhyme said. It was a large deformed palm, indeed grotesque, not with the elegant swirls and bifurcations of friction ridges but a mottled pattern of tiny lines.
"It's a wonderful picture--you're a virtual Edward Weston, Amelia. But unfortunately it's not a hand. Those aren't ridges. It's a glove. Leather. Old. Right, Mel?"
The technician nodded.
"Thom, write down that he has an old pair of gloves." Rhyme said to the others, "We're starting to get some ideas about him. He's not leaving his FR prints at the scene. But he is leaving glove prints. If we find the glove in his possession we can still place him at the scene. He's smart. But not brilliant."
Sachs asked, "And what do brilliant criminals wear?"
"Cotton-lined suede," Rhyme said. Then asked, "Where's the filter? From the vacuum?"
The technician emptied the cone filter--like one from a coffee-maker--onto a sheet of white paper.
Trace evidence . . .
DAs and reporters and juries loved obvious clues. Bloody gloves, knives, recently fired guns, love letters, semen and fingerprints. But Lincoln Rhyme's favorite evidence was trace--the dust and effluence at crime scenes, so easily overlooked by perps.
But the vacuum had captured nothing helpful.
"All right," Rhyme said, "let's move on. Let's look at the handcuffs."
Sachs stiffened as Cooper opened the plastic bag and slid the cuffs out onto a sheet of newsprint. There was, as Rhyme had predicted, minimal blood. The tour doctor from the medical examiner's office had done the honors with the razor saw, after an NYPD lawyer had faxed a release to the ME.
Cooper examined the cuffs carefully. "Boyd & Keller. Bottom of the line. No serial number." He sprayed the chrome with DFO and hit the PoliLight. "No prints, just a smudge from the glove."
"Let's open them up."
Cooper used a generic cuff key to click them open. With a lens-cleaning air puffer he blew into the mechanism.
"You're still mad at me, Amelia," Rhyme said. "About the hands."
The question caught her off guard. "I wasn't mad," she said after a moment. "I thought it was unprofessional. What you were suggesting."
"Do you know who Edmond Locard was?"
She shook her head.
"A Frenchman. Born in 1877. He founded the University of Lyons' Institute of Criminalistics. He came up with the one rule I lived by when I ran IRD. Locard's Exchange Principle. He thought that whenever two human beings come into contact, something from one is exchanged to the other, and vice versa. Maybe dust, blood, skin cells, dirt, fibers, metallic residue. It might be tough to find exactly what's been exchanged, and even harder to figure out what it means. But an exchange does occur--and because of that we can catch our unsubs."
This bit of history didn't interest her in the least.
"You're lucky," Mel Cooper said to Sachs, not looking up. "He was going to have you and the medic do a spot autopsy and examine the contents of her stomach."
"It would've been helpful," Rhyme said, avoiding her eyes.